Video transmission and conferencing networks (which, of course, usually include audio information) require up to date configuration information (including scheduling information) and call management information which we will refer to as directory management services. From one point of view, that of maintaining current information simply it would be preferable to have all information concentrated at a single location, for instance with the node controller (CNC) of the network. As these types of networks can be extremely large with many sites, it would seem that distributing this information across many sites would permit more efficient network operation; however, that would necessitate more complex management of the configuration and call management information as updating alone would have to be done at all information storage sites and the site information would be required to be kept updated (in "synchronization").